As a conveying apparatus conveying a container which accommodates a semiconductor wafer in a clean room or the like, a conveyor type conveying apparatus which uses a plurality of rollers is known. For example, Japanese Patent Application Laid-Open No. 2002-534800 proposes a conveying apparatus in which a plurality of rollers comprising driving rollers and running rollers are arranged in two rows in the conveying direction. Japanese Patent Application Laid-Open No. 2003-524544 proposes a conveying apparatus comprising a driving rail on which a plurality of rollers are arrayed in the conveying direction and a support rail which is arranged substantially parallel to the driving rail.
If the intervals between adjacent rollers are large, several problems arise. First, a conveying target object tends to vibrate vertically. Dust produced by a driving mechanism which drives the rollers readily passes through the rollers to diffuse in a clean room. Therefore, plates that block the gaps between the adjacent rollers must be arranged, as described in Japanese Patent Application Laid-Open No. 2003-524544. Accordingly, the narrower the intervals between the adjacent rollers, the better.
Also, each roller is desirably provided with a portion which guides the conveying target object so as not to fall off from the rollers. For example, the running roller of Japanese Patent Application Laid-Open No. 2002-534800 has a large diameter taper at its end to guide the conveying target object to the center of the roller. However, to form such a taper, the intervals between the adjacent rollers tend to increase.